How can i find treeview node by which label equals string variable?

c++, winapi

Solution

The treeview control does not provide an API to search for a label. You will have to manually traverse the items and compare them to your string.

If your treeview is more than one level deep you will have to decide how to traverse the items (either depth first or breadth first). In case there are multiple items with the same label these strategies may return different items.

An implementation might look something like this:

// Helper function to return the label of a treeview item
std::wstring GetItemText( HWND hwndTV, HTREEITEM htItem )
{
    static const size_t maxLen = 128;
    WCHAR buffer[ maxLen + 1 ];

    TVITEMW tvi = { 0 };
    tvi.hItem = htItem;         // Treeview item to query
    tvi.mask = TVIF_TEXT;       // Request text only
    tvi.cchTextMax = maxLen;
    tvi.pszText = &buffer[ 0 ];
    if ( TreeView_GetItem( hwndTV, &tvi ) )
    {
        return std::wstring( tvi.pszText );
    }
    else
    {
        return std::wstring();
    }
}

This is where the actual traversal takes place. The function is called recursively until no more items can be searched or a match has been found. This implementation uses a case-sensitive comparison (`wstring::operator==( const wstring& )`). If you need a different predicate you will have to modify the implementation as you see fit.

HTREEITEM FindItemDepthFirstImpl( HWND hwndTV, HTREEITEM htStart, const std::wstring& itemText )
{
    HTREEITEM htItemMatch = NULL;

    HTREEITEM htItemCurrent = htStart;
    // Iterate over items until there are no more items or we found a match
    while ( htItemCurrent != NULL && htItemMatch == NULL )
    {
        if ( GetItemText( hwndTV, htItemCurrent ) == itemText )
        {
            htItemMatch = htItemCurrent;
        }
        else
        {
            // Traverse into child items
            htItemMatch = FindItemDepthFirstImpl( hwndTV, TreeView_GetChild( hwndTV, htItemCurrent ), itemText );
        }
        htItemCurrent = TreeView_GetNextSibling( hwndTV, htItemCurrent );
    }

    return htItemMatch;
}

The following function wraps the recursion and passes the root element as the starting point. This is the function you would call in your code. It will return an `HTREEITEM` if one is found, `NULL` otherwise.

HTREEITEM FindItem( HWND hwndTV, const std::wstring& itemText )
{
    HTREEITEM htiRoot = TreeView_GetRoot( hwndTV );
    return FindItemDepthFirstImpl( hwndTV, htiRoot, itemText );
}

Problem

Original source